A few suggested features

[jokokoloko]

Just a quick list of some features that can be found in other frameworks and plugins that would be very nice to see built into Bootstrap:

Easy to style radio buttons and checkboxes
http://foundation.zurb.com/docs/components/custom-forms.html

Easy to style file upload component (especially the image upload variation)
http://jasny.github.io/bootstrap/javascript.html#fileupload

This thing called "Interchange"
http://foundation.zurb.com/docs/components/interchange.html

Responsive lightboxes
http://foundation.zurb.com/docs/components/clearing.html

Wizard
http://exacttarget.github.io/fuelux/#wizard

More example templates such as for a blog and contact page
http://foundation.zurb.com/templates.php

[cvrebert]

Easy to style radio buttons and checkboxes

Except for buttons, Bootstrap generally has a policy of not completely restyling native form controls.

[mdo]

If you want all of Foundation's features, perhaps use Foundation :).

We wont be doing custom forms in the main repo any time soon—search the issues for more on that.

Modals are responsive in v3—not exactly "lightboxes", but better than nothing.

Wizards aren't our thing—we won't be doing that.

More templates? Yup, we'll get on that in v3.1. Already tracking that in #9397.

[cvrebert]

See also #1982 regarding wizardry.

[cvrebert]

Also, we're planning on trying to help organize/formalize the BS add-on/plugin community in the future; see twbs/bootstrap-expo#424
A lot of what you mention makes a lot of sense as add-ons.

[jokokoloko]

Didn't know about the policy regarding native form controls, thanks for informing me!

Organizing/formalizing the add-on/plugin community is good enough for me! Thanks!

Foundation hurts my eyes ;(